Telautography or phototelegraphy



June 26, 1928. 1,674,881

- H: G. BARTHOLOMEW ET AL TELAUTOGRAPHY OR PHOTOTELEGRAPHY 3 Sheets-Sheet 1 Filed 001;. 12, 1923 Zomeau Ian/lame, 3%.

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Patented June 26, 1928.

UNITED, STATES PATENT OFFICE.

HARRY GUY BARTHOLOMEW AND MAYNARD L. D. HOFARLANE, 0F LON DON, ENGLAND.

TELAUTOGRAPHY OR PHOTOTELEGRAPHY.

. Application filed October 12, 1923, Serial No. 668,243, and in Great Britain October '16, 1922.

This invention relates to telautography or phototelegraphy.

In the specifications of our applications for British Letters Patent No. 195,577 and No. 197,402, we have described certain methods of telautography involving inter alia the production of an intermediate rec- 0rd of the original in the form of a punched tape of the character employed in the five unit code, that is to say, a punched tape in which each unit consists of a group of holes arranged transversely to the direction of travel of the tape, and in the specifications in question there is described the employment of a tape of this character in controlling directlythe exposure of successive small areas of a light sensitive surface in order to produce thereon a Visual representation of the original.

The main object of the present invention is to provide an apparatus having an optical system enabling the exposure to be conveniently controlled in'thismanner.

The invention consists broadly in an ,apparatus in which the perforated tape 0perates directly to permit or interrupt the passa e of light to the light sensitive surface from a suitable source comprising an optical system adapted to secure the projection on to the li ht sensitive surface of an image or spot 0% light the form of which shall be substantially independent of the number of individual holes constituting a groupthrough which the light forming the image is simultaneously passing.

Theinvention consists in various novel features, constructions and combinations of parts as will hereinafter appear and be specifically pointed out in the appended claims.

By these meansthe light passing through the several holes of a group which if a profjection dens of the usual form without modification were used would form a plurality ofspots or light side by side on the light sensitive surface, or at best a band of light, is concentrated or caused to converge b the firstlens to a straight line in one; plane while the second lens causes the lateral converging of .said line to a point, with the result that a spot of light which is of a width substantially equal to its height may be projected independently of the number of holes constituting the group through which light is passing.

Satisfactory gradation cannot be secured holes and so on, as the by the employment of tones produced by exposing a light sensitive surface to light, the intensity of which varies directly and in simple relationship with the number of the dots; that is to say, the desired grada this manner.

The invention also extends to the provision of means for securing the desired steepness of gradation.

Such means may comprise any suitable device for securing the passage. through the several marking holes constituting a group, of light the intensity of which varies in acploxl'dance with the position of themarking Thus, for example, in the gate, apertures may be arranged in a plate 337 at the gate 36 positioned to register with a plurality of holes in a group, such apertures being wider atone end 10 than at the other 10, the narrower end being adjacent that, over which the hole representing the lightest tint will pass. It is found that with a. tape of the character indicated in which the tones are ever, to he remarked that the invention is not limited to devices provided with apertures of this form.

As will be understood by those acquainted with the perforating and reperforating machines used in telegraphy, feed holes are formed in the tape and with a tape in which the maximum number of marking holes representing the maximum depth of tone is five these feed holes come between the second and third of the holes of a group.

It is not desirable that the light should be permitted to pass through these feed holes as the tonalit-y of the reproduction would thus be degraded.

The invention includes the provision of means whereby these holes are obscured.

In the preceding paragraphs apertures in the gate have been referred to, the plural be ing used to include the singular, as while a Q larly in a continuous or intermittentmanner.

It is found preferable to move both the ta e and the light sensitive surface continuous y and to arrange the light sensitive surface upon a cylindrical mandrel to which is imparted a rotatory and translatorymotion so that the light projected upon the light sensitive surface is caused to travel over the same ina helical path.

One construction in accordance with the invention is illustrated by way of example in the accompanying drawings Figure 1 bein a longitudinal section in a vertical plane 0 the essential ortion of the projector and the device adap d to contain the light sensitive surface.

Figure 2 is a corresponding sectional plan view;

Figure 3 a view of a detail, and

Fi ure 4 a front view of the projector with the ace plate and lenses removed to expose, the apertures in the gate.

The apparatus comprises a fixed source of light of substantially constant intensity acting as illuminating means for the holes in common.

A' casing 2 is arran ed to contain the spools 3, 3 journalled on s afts 5, 5", guiding the perforated tape 35 through a gate 36. The

ate comprises a front member 8, a rear mem er 7, and agate plate 9. Rays from a source of 1i ht such as an electric arc lamp pass throug an aperture 38 in the wall 1 of the chamber containing said are lamp and strongly illuminate the tape passing through the gate 36. On the front wall of the casing co-axially with the gate 36 is carried the lens mounting 14 OOIIIPI'lSlIl' an inner stationary member 15 and draw tu e 16. Arranged on a stationary tube carried'on the base of said mounting are arranged the two plano c lindrical' lenses 33, 34 with their longitu inal axes at right'angles to one another. On the draw tube 16, fitted with a handling cap 20, is mounted a microscope objective 17.

The sensitized film 29 on which the light passing through the punched tape is to fall is arranged within a light ti ht casing 32, on a mandrel=30 mounted on a s aft. 31. An aperture 28 is provided for the passage of the pencil of light passing through the microscope objective 17 and this aperture may be closed by a slide 23.

The pair of lenses 33, 34 of cylindrical form'are employed one arranged behind the other, the one 33 ad'acent to the ta e having its axis parallel wit the axes of t e groups of holes while the other 34 is arranged with its axis at right angles to the axis of the firstmentioned lens.

As will be understood, the cylindrical lenses are merely longitudinal sections of cyl- I inders havin one convex cylindrical.

The punc ed tape 35 is caused to travel through agate 36 ada ted to permit light to pass simultaneously t rough a single group of holes only, the optical system comprising the cylindrical lenses being arranged between the gate and the light sensitive surface. 4

Alternatively, an astigmatic optical system or lens of any suitable form adapted to secure the projection on to the light sensitive surface of an image, the form of which shall be substantially independent of the number of individual holes constituting a group through which the light forming the image is simultaneously passing, may be employed.

For example, any optical system (of which many. forms are known) may. be employed in which the source of light (rather than the openings) is imaged on the film. In this case the apertures are utilized to regulate .the amount of light passedonto the film and not as an object-to be imaged.

In the specific lens system herein illustrated, as well as in other systems, which would "accomplish the same purpose, the tape and film must be properly located with respect to the lenses and the curvature of said lenses, so that the above-mentioned desired effect can be secured.

Having now described our invention, what trate said light passing to'said sensitive sur-- face to form a single spot upon said surface and means to move said light sensitive surface and intermediate record, so that consecutive points on said record control the light falling on. consecutive pointso'f said surface. 7""

2. Apparatus for use in telephotography adapted automatically to produce a reproduction of a transmitted original comprising a source of light, means for supporting a light sensitive surface, optical means for projecting an ,image of the source of light upon said llght sensitive surface, means to support an intermediate record of said origilUU we claim as new and desire to secure by Letnal in the form of a non-pictorial representation sitioned to contro light passlng from said ight source to said light sensitive surface, and means to move the light sensitive surface and intermediate recordso that consecutive points on said record control the light fallingon consecutive points of said light sensitive surface.

3. Apparatus as claimed in claim 1, in which the non-pictorial representation is arranged in the path of light passing from the light source to a light sensitive surface, the

amount of light falling upon the light sensitive surface being directly controlled by the light transmitting characteristic of successive portions of said record.

4. Apparatus as claimed in claim 1, in which themeans for maintaining and guiding said intermediate record comprise a ate provided with an elongated aperture wlder at one end than the other, the narrower end being at that side of the gate overwhich the ortlon of the intermediate record representing the lightest tint of the original is-moved.

5. Apparatus as claimed in claim 1, in which the means for moving said light sensitive surface comprise a mandrel and means for simultaneously rotating and causing longitudinal movement of said mandrel.

6. Apparatus as claimed in claim 2, in which said optical means comprise two lano cylindrical lenses arranged on the longitudinal axis of the path of the light, with their plane surfaces toward the series of light and g at right angles to each other.

7. In combination a source of light, a perforated tape or the like having a plural.- ity of series of perforations, the combined area of each said series corresponding to the tone valve of. a small area of a picture to be reproduced, means adapted to support and move said tape in front of said source of light so that the light can pass through said perforations, means adapted to concentrate the light rays passing through said erforations to a single spot of light, an means adapted to project said spot of light on a light sensitive surface.

8. Apparatus for use in telephotography adapted to producev a reproduction of a transmitted original comprising a source of light, means for supporting a light sensitive surface, optical means for projecting light from said source upon said surface and means to control the light passing from said light source to said light sensitive surface and optical means to concentrate said light passmg to said sensitive surface to form a single spot upon said surface.

9. Apparatus as claimed in claim 1 in which the means adapted to concentrate the light passing to the light sensitive surface comprise-optical means acting to form a single spot of light thereon of constant sha e 10. Apparatus for use in telephotograp 1yv as claimed in claim 8, in which said optical means comprise lenses adapted to bring to a point on said light sensitive film rays' travelling from said light source to saidlight sensitive surface in planes substantially at right angles to one another.

In testimony whereof we have signed our names 'to this specification.

HARRY GUY BARTHOLOMEW. MAYNARD L. D. MQFARLANE; 

